Problem: Simplify the expression. $(4p-5)(5p+4)$
Explanation: First distribute the ${4p-5}$ onto the ${5p}$ and ${4}$ $ = {5p}({4p-5}) + {4}({4p-5})$ Then distribute the ${5p}.$ $ = ({5p} \times {4p}) + ({5p} \times {-5}) + {4}({4p-5})$ $ = 20p^{2} - 25p + {4}({4p-5})$ Then distribute the ${4}$ $ = 20p^{2} - 25p + ({4} \times {4p}) + ({4} \times {-5})$ $ = 20p^{2} - 25p + 16p - 20$ Finally, combine the $x$ terms. $ = 20p^{2} - 9p - 20$